Air Quality
(Last Updated June 2010)
For Alliance Alerts involving air quality, click here.
Alliance Position:
The Alliance supports policies to encourage new technology-based solutions, including higher vehicle gas mileage standards to reduce carbon dioxide and green house gases, and believes the region should be held harmless for airborne ground level ozone generated outside and transported into the region.
Current Status:
Air quality in the metropolitan Washington region is improving dramatically. In the 1980s, the region averaged 17 Code Red (unhealthy for all) days. In this decade, the average is less than 3. In 2009 there were zero.
This progress has ocurred despite dramtic increases in population, registered vehicles and vehicle miles traveled, in large part due to technological advances in fuel and engines.
For current air quality forecasts, click here.
Click here for a recap of the 2009 Ozone Season.
For a recap of ozone activity from the summers of 2004-2008, click here.
For more on regional air quality trends and our future outlook, click here.
Brief History of EPA's Ozone Standards:
In 1971 the Enivronmental Protection Agency (EPA) established a 1-hour ozone standard of .08 parts per million (ppm). In other words, if an ozone monitor in a particular area were to record ozone levels at .08 ppm or higher within a 1-hour time period, the entire region would be considered in violation. The Code Orange designation was not yet used, meaning a region was either Code Green, Yellow, or Red.
In 1979, the EPA revised the 1-hour standard upwards to .12 ppm, making it easier for the region to stay in conformity. Despite this adjustment, the Washington Metropolitan region averaged 17 Code Red days per year in the 1980s.
In July 1997, the EPA replaced the 1-hour standard with an 8-hour standard set at .08 ppm. The 8-hour standard is more difficult to meet because any exceedence over an 8-hour period (as opposed to only one hour) is considered a violation. With the 8-hour standard came the introduction of the Code Orange (unhealthy for sensitive groups) designation, which previously would have been considered part of the Code Red (unhealthy for all) category. Introduction of the Code Orange category was an acknowledgement that the Code Red category had been too broad.
As the number of Code Red days declined due to technological advances, the environmental community and media began treating Code Orange days as Code Red days with the implication that air quality was getting worse for everyone, when infact it was improving.
On March 12, 2008, the EPA strengthened its national ambient air quality standards by lowering the threshold from .08 ppm to .075 ppm. As a result, the region is likely to achieve more Code Orange or worse air quality days not because our air is increasingly unhealthy, but because the standards are more rigorous.
The EPA is currently reviewing the ozone standard and will likely issue a more stingent rule in August 2010.
EPA’s Ozone Air Quality Index Breakdown:
The AQI is an index for reporting daily air quality ranging from 0 to 500. The higher the AQI value, the greater the level of air pollution and the greater the health concern.
An AQI level of 100 generally corresponds to the national air quality standard, which is the level the EPA has set to protect public health. AQI levels below 100 are generally thought of as satisfactory, while levels above 100 are considered unhealthy for at risk groups, and then for everyone as the AQI rises.
|
|
 |
||||||||||||||||||||||||
|
An AQI of 100 for ozone corresponds to an ozone level of 0.075 ppm (averaged over 8 hours).
|
Air Quality Index |
Meaning |
Steps to Protect Your Health/Environment |
| Good (0-50) |
Air quality is considered good, and air pollution poses little or no risk. | Enjoy the great outdoors. Rather than drive, bike or walk. Conserve energy. Plant a tree. |
| Moderate (51-100) |
Air quality may pose a moderate health risk, especially for those who are unusually sensitive to air pollution. | Bundle errands to eliminate unnecessary trips. Perform regular maintenance on your car. |
| Unhealthy for Sensitive Groups (101-150) |
Members of sensitive groups, children and adults with respiratory and heart ailments, may experience health effects and should limit time spent outside. The general public is not likely to be affected. | Don't drive alone - carpool or take public transit. Refuel your car in the evening. Put off lawn care until air quality improves. Use a gas/electric grill instead of charcoal. |
| Unhealthy (151-200) | Everyone may experience health effects and should limit their outdoor activity; members of sensitive groups may experience more serious health effects. | Air is unhealthy to breathe. Telework and take public transit. Turn off lights/electronics when not in use. Avoid lawn maintanence. |
| Very Unhealthy (201-300) |
Everyone may experience more serious health effects and should avoid outdoor activities, especially individuals with heart and breathing ailments, children, and older adults. | Follow all action steps. |
Ground Level Ozone
Ground level ozone is a colorless gas formed through chemical reactions on hot days. Washington's hot, humid climate and location downwind from Midwestern power plants are major contributors to the region's ozone situation.
Ozone Components: Ozone consists of Volatile Organic Compounds (VOC) and Nitrogen Oxides (NOx).
VOC: Are formed by fossil fuel combustion and evaporation of gasoline, solvents, paints, etc.
NOx: Are the result of fossil fuel combustion. Tends to increase at higher and lower speeds. Congested highways generate lots of NOx.
Key Point:
Newer, cleaner fuels and other technologies are producing dramatically cleaner air. Check out this article from the Washington Post for more information on technology, clean air and greenhouse gases.